The present invention pertains to marine seismic exploration and more particularly to marine seismic exploration using air guns as acoustic seismic pulse generators.
In present marine seismic exploration a marine vessel having seismic pulse generators and or used in conjunction with a plurality of acoustic pulse detectors is used. Normally, a string of air guns are towed behind the marine vessel and are used as seismic acoustic pulse generators. A line of acoustic pulse detectors, such as geophones, may also be towed behind the marine vessel or may be laid on the ocean floor.
The string of air guns may be fired simultaneously or sequentially and may be of varied sizes. An air gun may have pressure requirements from 100 PSI to 5000 PSI. Each air gun normally has its own high pressure hose connection to the marine vessel. For example a string of twenty air guns will have twenty high pressure air hoses coming in the stern of the marine vessel, connecting to a single air compressor or high pressure air source. Each air hose is a different length and is wound on a reel when not in use. During deployment of the air guns the air hoses are unwound from the reel while fluid coupling between the air base and the high pressure source must be maintained.
Prior art has taught several methods for maintaining fluid coupling, however, the present trend is to increase the number of air guns and the pressure at which the guns are operated. The increased pressure requirements have rendered previously used prior art methods inoperative. Furthermore, an increase in the number of air guns used normally requires that the entire system be replaced with a system with additional gun capability. Thus, the addition of a few air guns represent a high capital expenditure.